Merged yesterday to the GCC Git development codebase for next year's GCC 17 release is the initial infrastructure laying out support for -std=c++29 and the like for targeting the C++29 standard not anticipated for release until around 2029.

With GCC's C++26 support continuing to come together, GNU Compiler Collection developers have begun laying out the infrastructure for experimentally supporting C++29 as they begin to land changes for supporting that follow-up revision to the C++ programming language.

Yesterday's commit introduced support for using -std=c++29 to specify C++29 or alternatively the -std=c++2d alias. Similarly, there is also the -std=gnu++29 variant for the GNU dialect of C++29.

That infrastructure work landed via [1]this commit by Red Hat compiler engineer Jakub Jelinek.

This early C++29 work follows the recent C++ committee meeting in Brno. Among the adopted features for draft C++29 include work on catching all undefined behavior in C++, designated initializaers for base classes, and other work on memory safety. See [2]this trip report by Herb Sutter as usual for an excellent overview of the recent C++ standards meeting.



[1] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=0c5c6249a2e9a75d2e7d1c6c434487c8dc077130

[2] https://herbsutter.com/2026/06/13/brno-trip-report/